4 bolt rear diff axle installation

[kilo4]

I just installed my 4 bolt rear diff and it's slipping. Does it matter which side the rear pass/driver axles are installed? I have the longer double spline long stub axle installed on the pass side.

 

[talondave]

I just installed my 4 bolt rear diff and it's slipping. Does it matter which side the rear pass/driver axles are installed? I have the longer double spline long stub axle installed on the pass side.

It shouldnt be slipping, you do have the axles installed right, so your good there!
Are you sure its slipping in the rear diff, and maybe not a broken tcase, or even a damaged trans?

 

[kilo4]

It's a new trans from Jack 4.2. The transfer case is also a rebuild from Jacks. It didn't slip until I switch to a 4 bolt diff. It ran fine with the 3 bolt rear end. About 200 miles after tranny break in. The car started slipping during take off. It felt like the rear end would engage/disengage. I could hear the axles trying to move but kept disengaging. I also noticed a leak under my rear diff. I looked closely and discovered the passenger side axle popped out of place. I reinstalled the axle and topped off the fluid, but it still slips and chatters. Could the rear diff VCU be damaged? It's a 4 bolt LSD rear diff.

 

[talondave]

It very well could be damaged... I know for sure that you have the axles installed right, cause I just installed a new passenger rear axle, and it was the longer splined shaft! When they get ran dry, the rear diff likes to make wierd chatter noises and slipping, which isn't your case cause you toped it off with fluid! Unless the previous owner ran it dry!!! So I would say, you definitely have a bad rear diff...

 

[kilo4]

The chances I take when buying a used rear diff I just did a test;
Test 1:
Jacked rear end and spun Rt rear wheel
Results: opposite wheel spun opposite direction. Spun smoothly with some resistance.

Test 2:
Rear end stayed on Jacks and disconnected drive shaft and spun Rt rear wheel
Results: opposite wheel stayed stationary and drive shaft pinion rotated smoothly with some resistance

Test 3:
Rear end stayed on Jacks and drive shaft remained disconnected. Spun Rt and Lt rear wheel assembly simultaneously
Results: differential pinion rotated smoothly with no resistance

*I'm not familiar with the differential internals, but are my results normal? Could I simply replace the VCU? Anyplace I can buy a good used rear diff VCU? I'm so close to sending this to TRE for an Evo3 rebuild with the correct gearing. I was told that an Evo3 rear diff is an overkill for drag racing.

*All test

 

[-red97rum-]

Are you sure it's not your clutch? I'm sorry if you ruled that out already but It doesn't hurt to ask.

 

[kilo4]

My QM twin disc was tested at Quarter Master USA on Feb 2011. All the noise is coming from the rear diff.

 

[GSXUAL]

TRE DSM REAR DIFFERENTIAL SERVICE
The viscous axle goes on the drivers side.
I had to replace it with a passenger side when they rebuilt my rear w/the evo3 and 12 plate.

It says at the bottom of the page "* Requires the driver's side axles stub to be replaced with the non-lsd 4-bolt rear axles stubs which plug into the rear diff which are tough, readily available and cheap."

But you can call him he'll talk your ear off for an hour about drivetrain
Really a nice guy. But hard to get a hold of.
But sounds like you need to just swap the axles.

 

[kilo4]

I wonder if it really matters which side because TalonDave had it the other way. I'm in process of dropping the diff to send to TRE. Unfortunately I failed to discuss the axles with Jon. He's already gone for the day to be with his girl.

 

[GSXUAL]

You can't use the double spline axle with the evo rear anyway so it dont matter anymore. Lol

 

[kilo4]

I'm swapping the axle and perform the same test.

I've been trying to install the longer axle stub on the driver side for 1hr and it won't go in. It looks like it only installs one way. The two sets if splinein passenger side.

 

[talondave]

Its got to be something wrong with rear diff! Its definitely not from having the axles wrong, cause like you said they won't switch....TRE has their info wrong on which axle is what on that page, either its a typo, or they have no clue!

Bad timing for you're issues kilo4, cause 1 month ago I through a 4bolt LSD rear diff away that was in perfect shape, besides a broken pinion gear! I could of just sent it to you for shipping cost, just to help you out! Oh well....damn me!!!..

 

[i3oi3c78]

Is it a rear diff. from a auto. or manual? What does the sticker say on the cover? They do have different gear ratios.

 

[kilo4]

Its got to be something wrong with rear diff! Its definitely not from having the axles wrong, cause like you said they won't switch....TRE has their info wrong on which axle is what on that page, either its a typo, or they have no clue!

Bad timing for you're issues kilo4, cause 1 month ago I through a 4bolt LSD rear diff away that was in perfect shape, besides a broken pinion gear! I could of just sent it to you for shipping cost, just to help you out! Oh well....damn me!!!..

Thanks Dave, I'm just going to reinstall my 3 bolt and send the 4 bolt to TRE for a rebuild. Tim from TMZ is getting a rebuild qoute together. Hopefully he gets it by Monday. I'm going to send it first thing Monday. I would like to rebuild it my self but I found no tutorials online.

 

[kilo4]

I removed the 4 bolt differential and looked inside. There's a chamfer inside the VCU splines. So the axles will only go in one way. Unless the differential can be assembled the other way. The same goes for the 3 bolt differential. Don't try to force the 2x axle stub in driver side like I did. I don't know what I broke but I heard metal snapped inside the differential.

- long 2x spline axle stub = passenger side
- short 1x spline axle stub = driver side

I hope this helps someone else installing rear axles.